Telemeter.



No 889,625. PATBNTED JUNE 2, 1908.

A. KUNIG & E. DUNITZ.

TELEMETER.

APPLIOATION'FILED JUNE 23, 1906.

20 straight boundary line, whic UNITED STATES PATENT OFFICE.

ALBERT KGNIG AND EMIL DGNITZ, OF JENA, GERMANY, ASSIGNORS TO THE FIRM OF CARL I ZEISS, OF JENA, GERMANY.

TELEMETER.

siding at Carl Zeiss strasse, Jena, in the Grand Duchy of Saxe-VVeimar, Germany,

have invented a new and useful Telemeter,

of which the following is a specification.

Theinvention consists in a variation of the well known coincidence telemeter, b which this instrument is rendered availab e to an improved method of measurement, which af fords with objects of very irregular outline r greater preeision, with objects of any other ind whatever a no less exact result than the coincidence process. Coincidence telemeters consist, as is already known, essentially of two telescopeswith ,a common ocular whose image fields are conti uous along a is approximate y parallel to that of the base line, and also of a device for producing a translation of pne of the images in the direction of the base The present invention depends u on two innovations in the arrangement of t e coincidence telemeter. Firstly, the straight boundary line between the image fields is arran ed )erpendicular to the base line.

Specification of Letters Patent. Application filed June 23, 1906. Serial No. 323,164.

Sec-

' Patented June 2, 1908.

a telemeter. Fig. 4 is a erspective View of the total prism system 0 another telemeterl Fig. 5 is a sectional lan view of a telemeter;

The lines .AA in l igs. l and 2 indicate the 'direction of the base hne, which consequentlyis assumed horizontal. The two images of a vessel at sea shown in each of Figs. 1 and 2 are congruent to one another and symmetrical about the straight boundary line of the image fields. One is the completely rerected image, the other that which is only erect in the direction perpendicular to the base The prism combination shown in Fig. 3 is suitable for producing the configuration of the two image fields according to Fig. 1, the combination shownin Fig. 4 forthe configuration according't'o Fig. 2, both under supposition of a horizontal base line. In Fig. 3 the. right angledi rism a, having reflecting perpendicularsur aces, serves as the separatlng rism, in whose edge, formed by the perpe'n icular surfaces, the common focal point b of the objectives is made to lie. Of the two objective r sms, the left one 0 produces, by means 0 the two reflectionsat its ridge surface, but-"which appear reduced to one i-If th case of the axialray impinging on theridg line as shown a complete rerectienof the image inverted by the objective;

30 0nd y, tie one image, referably the translatable one, is reversed with respect to the boundary line. With the instrument "thus transformed, the distance of an ob'ect is measured in the following manner. y di- 35 recting the instrument in the sighting plane the non-translatable image of the object is brougiit in proximity to the boundary line, and t en the other image is translated so far until it is likewise brought in proximity to 40 the boundary line with just the same lateral distance from it, that is, until both ima es lie symmetrical to the boundary line. eeause of the certain comparability of the short distances of corresponding points of 45 these images from the boundary line and because of the multiplicity of pairs of points whose two distances can be compared, an especially satisfactory exactness of measurement is attained by the symmetry process 50 described.

I In the annexed drawings; Figure 1 is a diagram of the combined image field of a telemeter. Fig. 2 is a diagram of the combined image field of another telemeter. Fig. 3 is a 55 perspective View of the total prism system of the reflection occurring once again at the separating prism a, however, produces lateral inversion. The image of the left telescope, thus inverted in the horizontal direction, occupies the left image field in Fig. 1. This imageis the one best chosen for translation, so that the translation (and measurement) device should be arranged on' the left side. The right objective prism d affords, besides the reerecting reflections at the ridge, yet a third, Whose effect, however, from the fourth reflection taking place at the separating prism a is neutralized, so that the right image field in Fig. 1 is occupied by the completely erected image of the right telescope.

.In the prism system according to Fig. 4, which produces a configuration of the image fields as in Fig. 2, the separating grism comprises the two parts a and a. urrounded by the cement layer joining the two parts lies a silver film (indicated by cross-hatching) which forms a standing semicircle and receives in the middle of the upright diametor the common focal point I) of the objec no ,tives. The silver film appears as a half ellipse in the combined image field, as represented in Fig. 2. This hal ellipse is occupied by the image produced by the rays of.

semicircle, which, however, neutralize each image.

.ing surface of the right objective other in their eiiect upon the position of the On the other hand the only reflect prism d effects lateral inversion, so that in the half elliptical image field the right telescope image yet a 1pears not completely reerected, but latera y inverted. The left telescope imageyhowever, located in the reater image field which'surrounds the hali ellipse, is only influenced by the ridge prism a and is in consequence'completely erected, because the left objective rism cpresents two refiecting surfaces W 'ch together have no effest on the position of the image.

.In the symmetry telemeter shown in Fig. 5 the prism system according to Fig. 4 is employed. The complementary lens system consists of the two objectives a and f, cemented to the objective risms c and d, and of the astronomical ocu ar g. By deviation of the right system of pencils, the measuring device roduces the translation of the ri ht (lateral y inverted) telesco e image rla tivel to its half elliptical rame. The indeX and the half erect scale i are visible through the window-7c. The scale is rigidly connected with the carrier Z of the deviating prism m. To the carrier 1, which stands with its foot in the slide-rest n, the rack 0 is connected, which, together with the inion p andoutside the casing g-the mille head in its slide-rest it.

What we claim as our invention, and desire to secure by Letters Patent, is.

A telemeter consisting of two telescopes and a device for translating bne of the telescope ima es in the direction of the base line, a sing e ocular being provided for both telescopes, a separating rism systemseparating the two lmage fie ds with a'straight boundary line perpendicular to the base line 4*, serves the purpose of moving the carrier 1 and the total prism combination of the instruinent rerecting one telescope image comletely and the other only with respect to the ase line.

In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses. ALBERT KONIG.

EMIL DONITZ.

Witnesses:

PAUL Kmienn, FRITZ SANDER. 

